Avalanche Forecast

Issued: Feb 15th, 2018 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Deep Persistent Slabs.

landon shepherd, Parks Canada

Jasper.

Take the time to carefully evaluate newly accessed terrain, large avalanches have been widespread over most aspects and elevations this week over the entire forecast area.

Summary

Weather Forecast

The edge of a series of troughs from the Aleutian Pacific region are being brought SE'ward through the forecast zone but are being kept mostly at bay by cold arctic air. Flurries are expected overnight but should result in less than 10cm of new snow. Clearing expected by the end of the weekend and into next week with sunshine and cold nights.

Snowpack Summary

The past week's storm snow has been redistributed by strong, variable direction winds. Where snow remains, new wind slabs overlie a settled upper snowpack which is sitting on the persistent weak layers in the mid snowpack. Widespread avalanche activity on these weak layers followed last week's storm, slopes without recent avalanches are suspect.

Avalanche Summary

Isolated windslab avalanches (likely failing on a persistent mid snowpack weakness, and up to size 2.5) were observed today in the Tonquin valley. East, South, and North aspects have formed windslabs and large cornices that have failed in the last 24 hrs in the north portion of the forecast zone.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Variable and strong upper elevation winds are continuing to create fresh windslabs.

Variable winds have created pockets of wind slab on all aspects.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

Persistent slabs remain a problem. Areas exposed to large triggers such as cornices or smaller avalanches / sloughing from above are most likely to trigger this midpack weakness.

Be wary of slopes that did not previously avalanchePay attention to overhead hazards like cornices which could easily trigger deep slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Feb 16th, 2018 4:00PM